So there was Ron Johnson, running for U.S. Senate, touring Joy Global's P&H mining equipment factory on National Ave. in July and not doing what candidates are supposed to do.

He didn't, for instance, try buttonholing the Wisconsin voters who were welding. Don't look at the arc, says the P&H guy leading the tour, and Johnson doesn't. Instead, he peers inside a giant boom, which is what you and I would do, since we're curious and not looking for votes. The tour passes a gear five feet in diameter. He touches it, naturally, though it casts no ballots.

Republicans hoped that Wisconsin's most masterful politician in 30 years, Tommy Thompson, would take on 18-year incumbent Sen. Russ Feingold this vulnerable year. They nearly got Terry Wall, a businessman with political experience.

Instead, they're likely to get Johnson, an Oshkosh plastics manufacturer with almost no engagement with politics until last fall (provided he beats underfunded Watertown businessman Dave Westlake in the primary).

Johnson lacks some customary tools. While he got noticed via a talk he gave at a tea party last year, he is merely a sufficient public speaker. He lacks glad-handing instincts: On a July tour of one of the state's largest schools, St. Anthony's in Milwaukee, he waves hello to lunch ladies but doesn't interrupt them to politick. To editors, he excitedly hands out holographic cards promoting his candidacy: The plastic is made by his company, Pacur, and he's proud of it. He enthuses like a guy who, until months ago, was all about plastic packaging instead of political packaging.

You can see him getting up to speed. The P&H tour is through an almost empty plant on summer shutdown, a briefing on how proposals to penalize coal would hit a big Wisconsin exporter (answer: very harshly). Johnson asks about cap-and-tax. He asks about how you ship a shovel the size of a house (in pieces, by train).

At St. Anthony's, he says hi to kids in summer school, but mainly he's learning about school choice. He admires it: He's "a big free-market guy," he says, and "in education, too." Then he spends half an hour over doughnuts talking with leaders of the heavily Latino school as he visibly shapes his stands on immigration. We can't rely only on fences, they tell him. He nods, explains, asks questions.

All of this fits Johnson's explanation as to why he's running: He's a citizen who got fed up with "what change we got" on a particular issue, the federalization of health care. He was provoked when last summer the Obama administration found it useful to demonize doctors as amputating limbs out of greed. Johnson says he's got a soft spot for doctors, since specialists saved his daughter's life as an infant years ago. "That was a bridge too far," he said of the political attacks. "They crossed a line."

Then Obamacare got shoved onto an unwilling nation, he says, and "at some point, people like me have got to get off the sidelines."

Which means he's got to brush up quickly on other issues, too. Feingold's surrogates have claimed Johnson is being heavily handled, filled with talking points on what the senator repeatedly insists are "extreme" positions. Yet Johnson freely confesses to his own beginner mistakes, such as saying "licensing" when he meant "permits" in an interview on guns.

Pressed by editors, he says his beef with the Democrats' agenda is that it "creates a high level of uncertainty" that intimidates business. He dismisses talk about changing birthright citizenship, cautiously lauds the drawdown in Iraq, says Republicans "went off the rails" with overspending and says "the way you raise revenue is you get the economy going again" rather than raising taxes.

He elaborates on answers, lacking the talking-point caution customary to candidates. You can see he's been thinking about this stuff lately, an intellectually curious man who spent the summer learning about trade by touching gears, thinking about how his principles apply to politics.

It's the look of a guy who didn't plan his life around winning office. It's refreshing to see.